Synthesis and characterization of surface-modified colloidal cadmium telluride quantum dots

Rajh, Tijana; Mićić, O. I.; Nozik, Arthur J.

doi:10.1021/j100148a026

Cited by 379 publications

(263 citation statements)

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“…In the last three decades since their fi rst reports appeared, [1][2][3][4][5] colloidal semiconductor quantum dots (QDs) attracted continuously increasing interest in different fi elds, including photonics [6][7][8][9][10] and optoelectronics. [11][12][13][14] Improving the characteristics and quality of QDs regarding synthetic Figure 1 a, a stable interface between the MeOH solution and the underlying NaCl-QD mixture instead of an instantaneous mixing is crucial for a successful crystallization.…”

Section: Introductionmentioning

confidence: 99%

Liquid–Liquid Diffusion‐Assisted Crystallization: A Fast and Versatile Approach Toward High Quality Mixed Quantum Dot‐Salt Crystals

Adam

Wang

Dubavik

et al. 2015

Adv Funct Materials

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2638www.MaterialsViews.com wileyonlinelibrary.com approaches, [ 15,16 ] effi ciency, [ 17,18 ] extending their spectral range [19][20][21] and environmental friendliness using less toxic materials [22][23][24] sparked industrial applications. Those started with the demonstration of a 40 in. display prototype presented by Samsung [ 25 ] and followed by the foundation of QD Vision, Inc., [ 26 ] whose QDs are now used in the latest series of Sony products. All of the mentioned applications require long-term stability of the QDs under various conditions including high temperatures as well as high intensity illumination. Packaging of the QDs within polymer or inorganic matrices is one way to address these issues, while improving the processability of the QDs at the same time. Commonly used polymers, such as polystyrene and poly(methylmethacrylate) [ 27 ] are relatively less stable and tight in comparison to their inorganic counterparts. Inorganic matrices on the other hand can incorporate the QDs directly from their melt, e.g., using the Czochralski approach, [ 28 ] coated as a thin fi lm directly on their surface [ 29,30 ] or, as recently developed by our group, grown as mixed crystals at ambient temperatures from a saturated salt solution. [ 31 ] Using this method, different types of QDs can be incorporated due to the low thermal stress and, by choosing the proper matrix-QD system, the photoluminescence quantum yields (PL-QYs) are enhanced upon incorporation. [ 32,33 ] Here, a new, fast, and versatile method for the incorporation of colloidal quantum dots (QDs) into ionic matrices enabled by liquid-liquid diffusion is demonstrated. QDs bear a huge potential for numerous applications thanks to their unique chemical and physical properties. However, stability and processability are essential for their successful use in these applications. Incorporating QDs into a tight and chemically robust ionic matrix is one possible approach to increase both their stability and processability. With the proposed liquid-liquid diffusion-assisted crystallization (LLDC), substantially accelerated ionic crystallization of the QDs is shown, reducing the crystallization time needed by one order of magnitude. This fast process allows to incorporate even the less stable colloids including initially oil-based ligandexchanged QDs into salt matrices. Furthermore, in a modifi ed two-step approach, the seed-mediated LLDC provides the ability to incorporate oilbased QDs directly into ionic matrices without a prior phase transfer. Finally, making use of their processability, a proof-of-concept white light emitting diode with LLDC-based mixed QD-salt fi lms as an excellent color-conversion layer is demonstrated. These fi ndings suggest that the LLDC offers a robust, adaptable, and rapid technique for obtaining high quality QD-salts.

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Section: Introductionmentioning

confidence: 99%

Liquid–Liquid Diffusion‐Assisted Crystallization: A Fast and Versatile Approach Toward High Quality Mixed Quantum Dot‐Salt Crystals

Adam

Wang

Dubavik

et al. 2015

Adv Funct Materials

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“…The refractive indices correspond to those for ZnTe and SiO 2 , which are the materials whose layers can be deposited by means of colloidal chemistry. 16,17 . The parameters of the QD are chosen to be similar to those for realistic QDs based on a II-VI semiconductor compound: ⌫ 0 ϭ2 …”

Section: Results and Discussonsmentioning

confidence: 99%

“…15 Recent progress in photonic crystal fabrication gives hope that the four-decade-long progression to lower dimensionality in exciton-polariton systems will soon achieve its logical conclusion with the appearance of photonic dots with embedded electronic quantum dots. In particular, technological advances in the fabrication of spherical objects by the techniques of colloidal chemistry, 16,17 and other methods 18 will hopefully provide a means for the practical fabrication of multilayered structures of spherical symmetry in due course.…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic theory of the coupling of zero-dimensional exciton and photon states: A quantum dot in a spherical microcavity

et al. 2001

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Additional information:Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Exciton-light coupling in spherical microcavities containing quantum dots has been treated by means of classical electrodynamics within the nonlocal dielectric response model. Typical anticrossing behavior of zero-dimensional exciton-polariton modes has been obtained, as well as the weak-coupling-strong-coupling threshold. The influence of the cavity Q factor on the optical response of the structure has been analyzed.

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“…Therefore, we have investigated whether it is possible to substitute (part of) the capping layer of CdTe quantum dots with a polythiophene (poly(4)) bearing a tetrahydro-4H-thiopyran-4-ylidene group in the side chain and whether this side chain induces substantial electronic contact between the polymer and the quantum dot. CdTe quantum dots were used particularly because of their relatively low bandgap (1.5 eV for bulk material [38] ), which enables the separation of the fluorescence emission bands of the quantum dots and the polythiophene. The complexation between the quantum dots and the polymer, and the optical properties of the hybrid systems, were investigated with UV/Vis absorption, fluorescence, and photoinduced absorption (PIA) spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

“…[38,55,56] The spread in CdTe quantum dot redox potentials is due to differences in measurement method (pulse radiolysis [38] and cyclic voltammetry in either a 5:1 (v/v) benzene/acetonitrile mixture [55] or aqueous solution [56] ). Furthermore, different capping agents (thioglycerol, [38] trioctylphosphine oxide, [55] or thioglycolic acid [56] ) were used. The values of DG 0 with the different sets of CdTe quantum dot redox potentials were calculated both when poly(4) was assumed to be the electron donor and when it was taken to be the electron acceptor (Table 1).…”

mentioning

confidence: 99%

Side Chain Mediated Electronic Contact between a Tetrahydro‐4H‐thiopyran‐4‐ylidene‐Appended Polythiophene and CdTe Quantum Dots

Beek¹,

Zoombelt²,

Jenneskens³

et al. 2006

Chemistry A European J

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Currently, many watershed models are available that have various complexities, strengths, and weaknesses. The basic mathematical foundations of these mathematical models are often overlooked due to high demands on convenient applications with graphical user interfaces. Although this and other factors are important while selecting a model, the mathematical foundation should also be taken into account, as performance or efficiency and accuracy of a model depend on its simplicity or complexity. A comprehensive review of 14 storm event watershed models was conducted. Hydrologic procedures (rainfall excess, flow routing, and subsurface flow) of the models are presented and compiled. Among the procedures, flow routing has the most influence on model performances (speed and accuracy). Overland and channel flow routing procedures using different flow‐governing equations, having various approximations and solved by different methods, are compared based on their relative levels of physical bases, complexities, and expected accuracies in simulating the dynamics of water flow. Models using more mathematical terms in the flow‐governing equations are more physically based and expected to be more accurate than models using approximations, however, are more complex due to more intensive but approximate numerical schemes (inefficient). Models using approximate equations with analytical solutions may provide a balance between complexity and accuracy. The review and comparisons are useful to modellers, water resources managers, and researchers in understanding the basic foundations of the models and making informed selections for practical applications or further developments. Other factors such as data intensiveness, user friendliness, and resource requirements are also important considerations. Copyright © 2011 John Wiley & Sons, Ltd.

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Synthesis and characterization of surface-modified colloidal cadmium telluride quantum dots

Cited by 379 publications

References 10 publications

Liquid–Liquid Diffusion‐Assisted Crystallization: A Fast and Versatile Approach Toward High Quality Mixed Quantum Dot‐Salt Crystals

Liquid–Liquid Diffusion‐Assisted Crystallization: A Fast and Versatile Approach Toward High Quality Mixed Quantum Dot‐Salt Crystals

Electromagnetic theory of the coupling of zero-dimensional exciton and photon states: A quantum dot in a spherical microcavity

Side Chain Mediated Electronic Contact between a Tetrahydro‐4H‐thiopyran‐4‐ylidene‐Appended Polythiophene and CdTe Quantum Dots

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